A group of about 50 people, mostly Nepali Sherpas, were hit by the avalanche at more than 20,000 feet, said Tilak Ram Pandey of the ministry's mountaineering department.

The avalanche took place just above base camp in the Khumbu Ice Fall.

Climbers and guides had been setting the ropes for the route, acclimating and preparing the camps along the route when the avalanche hit Friday, said Gordon Janow with Alpine Ascents International in Seattle.

All 50 to 60 climbers were Nepalese locals and Sherpas who were taking food and supplies to the camps, Pandey said.

The climbers are all now accounted for, Pandey said. "Rescue teams have gone ... to look for the missing."

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Climber: Avalanche victim was my equal03:42

Photos:Exploring Mount Everest

Photos:Exploring Mount Everest

The journey to the summit of Mount Everest is a challenge an increasing number have taken on since the summit was first reached in in 1953 by Sir Edmund Hillary and Tenzing Norgay. Until the late 1970s, only a handful of climbers per year reached the summit. By 2012 that number rose to more than 500.

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Photos:Exploring Mount Everest

Explorers are seen in 1922 at Camp II on the East Rongbuk Glacier. That same year, seven Sherpas were killed when they were caught in an avalanche during an expedition led by George Mallory.

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Photos:Exploring Mount Everest

George Mallory and Edward Felix Norton reach 27,000 feet on the northeast ridge of Everest in 1922. They failed to reach the summit.

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Mallory returns to Everest In June 1924. He's seen here with his climbing partner Andrew Irvine at the base camp. This is the last photo of the the two before they disappeared on the mountain. Mallory's body was found 75 years later, showing signs of a fatal fall.

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Mountaineers are seen preparing to leave their camp during one of Eric Shipton's early expeditions on Everest in the 1930s. While Shipton never made it to the summit, his exploration of the mountain paved the way for others.

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Shipton leads an expedition exploring the Khumbu Glacier icefall in November 1951.

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Shipton is also known for discovering and photographing footprints of an unknown animal or person, like this one taken in 1951. Many attributed these to the Yeti, or Abominable Snowman.

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Edmund Hillary sits at base camp in May 1953 before heading out on what would become the first successful ascent to the top of the world.

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Hillary and Nepalese-Indian mountaineer Tenzing Norgay climb beyond a crevasse on Mount Everest in 1953. Upon meeting George Lowe, who had climbed up to meet the descending duo, Hillary reportedly exclaimed, "Well George, we knocked the bastard off!"

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Members of a U.S. expedition team and Sherpas are shown with their climbing gear on Everest. The team, led by Jim Whittaker, reached the top on May 1, 1963, becoming the first Americans to do so.

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Whittaker's team members climb Everest's West Ridge in 1963.

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On April 5, 1970, six Sherpas died in an avalanche at the Khumbu Icefall. The icefall, at the head of the Khumbu Glacier, seen here in 2003, is one of the more treacherous areas of the ascent.

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British Army soldiers and mountaineers John "Brummie" Stokes and Michael "Bronco" Lane above the icefall at the entrance to the West Col (or western pass) of Mount Everest during their successful ascent of the mountain. The joint British-Nepalese army expedition reached the summit on May 16, 1976.

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In 1978, Reinhold Messner makes the first ascent without supplemental oxygen. Messner is seen here at Munich Airport showing reporters his frozen thumb after climbing to the top of Nanga Parbat in Pakistan, alone and without an oxygen mask.

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French climber Jean-Marc Boivin becomes the first person to paraglide from Everest's summit in September 1998.

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The 1996 climbing season was one of the deadliest, when 15 people died on Everest, eight in a single storm in May of that year.

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Francys Distefano-Arsentiev became the first American woman to reach Everest's summit without bottled oxygen on May 23, 1998. However, she and her husband, Sergei Arsentiev, never made it off the mountain. They died after becoming separated while attempting to descend in the dark. At least one climbing party found Francys barely conscious, but there was nothing they could do to save her. Her husband's body was found years later. It is believed he fell while trying to save his wife.

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Pemba Dorje Sherpa and Moni Mulepati became the first people to get married on Everest's summit, on March 30, 2005. The couple are seen here waving from base camp on June 2, 2005.

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Sherpa climbers pose at Everest Base Camp after collecting garbage during the Everest cleanup expedition on May 28, 2010. A group of 20 Nepalese climbers collected nearly two tons of garbage in a high-risk expedition to clean up the world's highest peak.

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Mountaineer Ralf Dujmovits took this image of a long line of climbers heading up Everest in May 2012.

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Jordan Romero became the youngest person to reach the summit, at age 13, on May 22, 2013. Jordan, right, is seen here on the summit with one of the Sherpas who helped him make the ascent.

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Yuichiro Miura, became the oldest person to summit Everest, on May 23, 2013, at the age of 80.

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Malavath Poorna, left, holds up her national flag on May 24, when the 13-year-old daughter of poor Indian farmers became the youngest girl to climb Everest.

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'I did not think I would survive'

One of those who survived is Wangdi Sherpa, 26, who was working with trekking firm Summit Treks to take 13 Britons to climb Everest.

He recounted how he and others were going to set up Camp II, above base camp, when disaster struck -- and it was only by chance that he was not among the victims.

"A big piece of ice suddenly came off the mountain. I did not think I would survive. I am very happy to have survived," said Wangdi, who has reached the mountain's summit three times before.

He and an assistant, who were attached to a safety rope, hid behind a piece of ice as the avalanche came tumbling down, he said.

"We could do that because we were in the front," he said. "Up to 12 of those behind us survived, but the ones after them died. Those who had already crossed ahead when the ice came off also survived.

"We stayed behind the ice for five minutes. By the time we reached base camp it was around 11 a.m. When the ice fell we saw nothing because of the dust," Wangdi said.

'There is always a risk of death'

This latest accident occurred during the spring climbing season, the busiest of the year.

Climbers arrive in April to acclimate to the altitude before heading toward the summit of the world's highest mountain. Ethnic Sherpas act as guides for the mostly foreign clients.

Now the question is whether the planned expedition will go ahead in the wake of Friday's tragedy.

"The Sherpas and the clients are not in a condition to talk to each other at the moment," said Jeewan Ghimire, of Shangri La Treks.

Four of his Sherpas are dead after the avalanche and one is missing.

"It could take a week more before a decision on whether the climb will go ahead will be taken," he said.

According to Ghimire, "A distance is being maintained between the two sides. The clients will have to accept the decision of the Sherpas."

"Our friends and brothers have died. There will be no question of doing anything without a discussion with everyone involved," said Pasang Sherpa, who also has been to Everest before.

"This is our job, so there is always a risk of death. We cannot say that there has been exploitation."

About 334 foreign climbers have been given permission to climb Everest over the next couple of months, with an estimated 400 Sherpas helping them, mountaineering official Dipendra Poudel said Friday.

From May 15 to 30 is usually the best window for reaching the 29,028-foot peak.

Lakpa Sherpa, who has twice reached the summit of Everest, lost his cousin Ang Kaji Sherpa on the mountain on Friday.

Despite that loss, he said safety standards have improved by 80% on what they were 10 years ago, because the Sherpas are better trained. He added, "There is always a risk in this job."

The deadliest year was in 1996

Before Friday, the deadliest single-day toll was from an accident in May 1996, when eight climbers disappeared when a huge storm hit. Their tragic story was chronicled in Jon Krakauer's bestselling book "Into Thin Air."

The deadliest year on Everest was 1996, when 15 people died. Another 12 climbers were killed in 2006.

Until the late 1970s, only a handful of climbers reached the top each year. The number topped 100 for the first time in 1993. By 2004, it was more than 300. In 2012, the number was more than 500.